Within recent years, an artificial suede-like leather made of extra fine fibers has been developed as a substitute for suede and the demand for such a material has been encouraged by the variety and choice of clothing materials in the fashion. To provide such a suede-like artificial leather, it has been known to produce a raised fabric by buffing the surface of a woven, nonwoven, or knitted fabric made of extra fine fibers, or further to process thus produced raised fabric by applying an elastic polymer such as polyurethane polymer, etc. The conventional suede-like artificial leather has an excellent trailing effect but fails to produce a lustrous and beautiful appearance which is proper to natural suede, or, in other words, it lacks a kind of three-dimensional feeling formed by lights and shades which is the result of the anisotropic or random arrangement of naps.
Several methods have hitherto been proposed to improve the appearance of a suede-like artificial leather.
For instance, Japanese Patent Application Laid-Open No. 106701/76 discloses a method for making a suede-like artificial leather having a pattern of three-dimensional feeling on its surface, comprising the application by printing and fixation of an aqueous liquid of polyvinyl alcohol, etc. on the woven or knitted fabric; the impregnation of the fabric with a solution of polyurethane for the purpose of effecting wet solidification; the elution of the water-soluble polymer after or at the time of extraction of the solvent of polyurethane polymer; and the buffing or brushing of the fabric after drying so that those parts where the water-soluble polymer is removed are raised as naps. However, the three-dimensional pattern made according to this method has an outline sharpness and fails to produce a feeling of such three-dimensional beauty of lights and shades resulting from the anistropic or random arrangement of the nap as seen with natural suede.
Japanese Patent Application Laid-Open No. 12903/77 discloses a method for preparing a suede-like artificial leather having a soft and beautiful nappy appearance comprising the impregnation of the raised fabric with an aqueous liquid of polymer such as polyvinyl alcohol, etc. having the viscosity of more than 100 cP; squeezing of the liquid from the fabric in the due direction (direction in which the nap is oriented) under the pressure of more than 1 kg/cm.sup.2 and drying of the fabric; impregnation of thus treated fabric with a water-insoluble polymer liquid such as polyurethane polymer followed by squeezing in the due direction; removal of the aqueous liquid of polymer by solution at the time of or after the solidification of the water-insoluble polymer; and buffing of the raised fabric after drying. Also in Japanese Patent Application Laid-Open No. 15801/77 a similar method, in which only a water-insoluble polymer is used, is disclosed. However, these methods can only provide a fabric whose nap is oriented uniformly in one direction and fail to produce a feeling of such three-dimensional beauty of lights and shades resulting from the anisotropic or random arrangement of the nap as seen with natural suede.